Genotypic variation in drought resistance in sorghum (Sorghum bicolor L. Moench)

Abstract

The response of 21 strains of Sorghum bicolor to drought was examined in a pot experiment under glasshouse conditions. Twenty‐eight‐days old plants of all the lines were subjected to 0 or 5 cycles of drought. Plant growth was measured as shoot fresh and dry matters and leaf area. The repeated cycles of drought caused significant reduction in all three characters. Nevertheless, five lines (GP 15 ICSV 233, GP.P.4.4 Pak SS 111, GP. 12. IC 1039, GP.20 Bagdar and GP 256 IZA 114) were consistently superior to the other lines in all three characters. Four lines (GP.13 ICSV. 1, GP.2 10919, GP.D11 YSS. 89 and GP 17 S.35) were categorized as drought sensitive on the basis of their relatively poor performance in all three characters. Osmotic adjustment showed a positive correlation with the degree of drought resistance in almost all lines. The drought resistant lines had significantly greater osmotic adjustment as compared with that of the drought sensitive lines. By contrast, discrimination between these lines was not possible using water retention capability (rate of water loss from excised leaves) since the drought resistant and drought sensitive strains had almost similar values of water retention capability.

The considerable amount of intra‐specific variation observed in this set of germplasm of sorghum can be of great value for further improvement in drought resistance in this crop through selection and breeding.

Key words:

• Intra‐specific variation
• screening
• osmotic adjustment
• water retention capability

STICHWÖRTER:

• Intraspezifische Variation
• Screening
• Osmotischer Ausgleich
• Wasserhältefähigkeit